跨越折扣分摊计算俩次月结之间的差额；

1.需求描述：由于本月可以修改历史成交单，在本月做月结的时候会将历史修改过成交单的月份重新做月结，现需求要求本次月结完后折扣与前一次月结折扣之间的差额 ；分摊到明细 ；

2.思路说明：

>1.首先找出做过跨越修改的成交单，及修改日期为当月 成交日期不为当月的记录；

>2.去分摊明细表中做对比 ；

SELECT B.DEALNO,
       B.DEALDATE,
       B.CREATETIME + 0,
       B.PRODUCTCODE,
       B.DEALCURRENCY,
       B.OUTCURRENCY,
       B.MEMBERID,
       B.BSFLAG,
       B.DISCOUNT,
       B.DISCOUNTCNY,
       B.DISCOUNTUSD,
       B.DISCOUNTAMOUNT,
       LAG(B.DISCOUNTAMOUNT, 1, 0) OVER(PARTITION BY B.DEALNO, B.BSFLAG /*,b.status*/ ORDER BY B.ID DESC) LAGAMOUNT,
       B.DISCOUNTAMOUNTCNY,
       B.DISCOUNTAMOUNTUSD,
       B.DISCOUNTTAX,
       B.DISCOUNTTAXCNY,
       B.DISCOUNTTAXUSD,
       B.STATUS,
       B.RNUM
       --,LAG(b.discount,1,b.discount) OVER (PARTITION BY b.dealno,b.bsflag/*,b.status*/ ORDER BY b.createtime DESC ) lag_discount
      ,
       B.DISCOUNTAMOUNT - LAG(B.DISCOUNTAMOUNT, 1, 0) OVER(PARTITION BY B.DEALNO, B.BSFLAG /*,b.status*/ ORDER BY B.ID DESC) LAG_DISCOUNTAMOUNT
  FROM (SELECT B.ID,
               B.DEALNO,
               B.DEALDATE,
               B.CREATETIME CREATETIME,
               B.PRODUCTCODE,
               B.DEALCURRENCY,
               B.OUTCURRENCY,
               B.MEMBERID,
               B.BSFLAG,
               B.DISCOUNT,
               B.DISCOUNTCNY,
               B.DISCOUNTUSD,
               B.DISCOUNTAMOUNT,
               B.DISCOUNTAMOUNTCNY,
               B.DISCOUNTAMOUNTUSD,
               B.DISCOUNTTAX,
               B.DISCOUNTTAXCNY,
               B.DISCOUNTTAXUSD,
               B.STATUS,
               ROW_NUMBER() OVER(PARTITION BY B.DEALNO, B.BSFLAG, B.STATUS ORDER BY B.ID DESC) RNUM
        
          FROM BASE_MEMBER_DEALER_DISCOUNT B
         WHERE B.DEALNO IN (SELECT M.NO
                              FROM HIS_PRODUCT_DEAL_MAIN M
                             WHERE TO_CHAR(M.MODIFYTIME, 'yyyymm') = '201709'
                               AND TO_CHAR(M.DEALDATE, 'yyyymm') <> '201709'
                               AND M.STATE = 9)) B
 WHERE RNUM < 3

 第二版

WITH A1 AS
---A1找出跨月修改的数据；37跳数据
 (SELECT M.NO A1NO
    FROM HIS_PRODUCT_DEAL_MAIN M
   WHERE TO_CHAR(M.MODIFYTIME, 'yyyymm') = '201709'
     AND TO_CHAR(M.DEALDATE, 'yyyymm') <> '201709'
     AND M.STATE = 9
  
  ),
A2 AS
--根据跨越修改的数据找到分摊数据 ；
 (SELECT *
    FROM (SELECT B.DEALNO A2NO,
                 B.PRODUCTCODE A2CODE,
                 B.BSFLAG B2BSFLAG,
                 B.DISCOUNTAMOUNT A2AMOUNT,
                 B.STATUS B2STATUS,
                 B.ISWRITEOFF,
                 ROW_NUMBER() OVER(PARTITION BY B.DEALNO, B.BSFLAG ORDER BY B.ID DESC) RN
            FROM A1 A
            LEFT JOIN BASE_MEMBER_DEALER_DISCOUNT B
              ON A.A1NO = B.DEALNO
           WHERE B.STATUS = 0 /* AND b.iswriteoff=0 AND EXISTS (SELECT 1 FROM A1 A WHERE  B.DEALNO  =  A.A1NO)  */
          )
   WHERE RN = 1)

-- FROM A1 A , BASE_MEMBER_DEALER_DISCOUNT B 
--  WHERE A.A1NO=B.DEALNO  AND  B.STATUS = 0  /* AND b.iswriteoff=0 AND EXISTS (SELECT 1 FROM A1 A WHERE  B.DEALNO  =  A.A1NO)  */ ) WHERE rn=1  )
SELECT * FROM A2; --45跳数据 应该为37*2=74条 ；

, A3 AS
--找到无效数据中最大id的那条数据 ；
(
  SELECT S.DEALNO A3NO,
         S.PRODUCTCODE A3CODE,
         S.DISCOUNTAMOUNT A3AMOUNT,
         S.BSFLAG B3BSFLAG,
         ROW_NUMBER() OVER(PARTITION BY S.PRODUCTCODE, S.DEALNO, S.BSFLAG ORDER BY S.CREATETIME DESC) RN
    FROM BASE_MEMBER_DEALER_DISCOUNT S
   WHERE S.STATUS = 1), A4 AS (SELECT AA2.A2NO,
                                AA2.A2CODE,
                                AA2.B2BSFLAG,
                                AA2.A2AMOUNT,
                                AA3.A3AMOUNT,
                                AA2.A2AMOUNT - AA3.A3AMOUNT AS CHAE
                           FROM A2 AA2
                           LEFT JOIN A3 AA3
                             ON AA2.A2NO = AA3.A3NO
                            AND AA2.A2CODE = AA3.A3CODE
                            AND AA2.B2BSFLAG = AA3.B3BSFLAG
                          WHERE AA3.RN = 1)
    SELECT * FROM A4;